EP 0 548 822 describes a light-transparent, IR-reflective body which consists of a plastic base material and a coating layer adhering thereto. The coating layer comprises from 20 to 40% by weight of a single-layered interference pigment. This body has the disadvantage that, besides the NIR radiation, some of the visible light is also reflected, and that the light passing through is green and the reflected light is red. Furthermore, the translucent coating layer means that the transparency of the base material is lost (milk-glass effect).
DE 2 709 562 discloses a plastic film for shading plants against sunlight which is perforated and is provided with a white or metallic-lustre pigment or with a white or metallic-lustre coating, so that from 10 to 70% of the perpendicularly incident light is allowed to pass through. A plastic film of this type reduces the radiation uniformly over the entire wavelength range, i.e. both in the visible region and in the infrared region. Used on buildings, this would result in darkening of interior rooms, but this may be disadvantageous.
EP 1 059 338 describes a composition for coating transparent surfaces, as used for greenhouses, sheeting structures, domelights, roof windows or roof covers, which has high transparency in the visible region of sunlight and high reflection in the NIR region. The paint consists of a multilayered interference pigment consisting of a transparent support material which is coated with alternating layers of a material of low refractive index and a material of high refractive index, and a polymeric, organic binder. This translucent, NIR-reflective paint also causes the transparency of the base material to be lost.
U.S. Pat. No. 3,887,744 describes a transparent plate which is partly coated on its surface with aluminum, which regulates the percentage transmission of visible light and infrared rays. Either certain areas of the plate are coated with aluminum or the aluminium is applied as an ink by screen printing. Although details from the environment are evident from within the enclosed area in the case of this type of coating, aluminum does not, however, reflect wavelength-selectively with respect to the solar spectrum. This means that aluminium, in contrast to interference pigments, reflects both NIR radiation and visible light, which results in a reduction in brightness in the enclosed area.